Mine had the same symptoms at about 30k. Dealer said plugs needed changing, I thought he was just trying to take me for the usual ride. I tried a lot of chemicals with little effect. Finally decided to take the plugs out and sure enough, they were burnt--gaps out to about .05 or something. Got new, cheap bosch platinums, gapped down to .030 and all problems solved, including chronic CEL. Read somewhere the prob. is that the ignition doesn't have the juice to make spark jump a wider gap, thus the stumbling/missing. The plugs claimed to be factory gapped BTW, but were way to wide out of the box. You might want to recheck yours and demand a refund for the MAP sensor (can the dealer say "Fraud"? I'll bet your state attorney general can.)